Since Ursa Mini 4.6 are shipping, the question is what are the Cfast cards to go for? The approved list is yet to show CFast cards that will record 4.6K Prores and 4.6K Raw. I hope BMD will soon add cards to its list. I remember I had problems with SSDs when I bought my BMPC4K. There was no approved list for BMPC. Assuming that the cards listed for BMCC would run on BMPC too, I landed up with dropped frames!

Independent filmmaker/producerOwner of post production facility for cinema including grading and creation of DCPs.

Yes, but the last update I saw is nine months old, June 15, 2015! The Lexar 3400x cards are there but they should say "discontinued"and the replacement cards, 3500x and 3600x, have not been approved yet by BMD. ARRI has approved the 3600x cards and failed the 3500x cards.

We have just had a report in another thread of failed media when using the Lexar 3600x cards in dual record mode. The problem apparently was repeatable. Don't have any other details, but this is worrisome.

Edit: perhaps the reference to 3600x cards was a typo and should be 3400x cards.

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Last edited by rick.lang on Tue Mar 22, 2016 8:18 pm, edited 1 time in total.

rick.lang wrote:We have just had a report in another thread of failed media when using the Lexar 3600x cards in dual record mode. The problem apparently was repeatable. Don't have any other details, but this is worrisome.

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Are you referring to this, Rick? "I've been using 128gig Lexar 3400x cards with the ursa 4k for a while, and they only work flawlessly when I use one card at a time. On two occasions when I have cards in both slots, when one gets full and the camera starts using the second card, the first card gets corrupt. I've been able to restore most, not all of the data from the first card by using diskdoctor, but it's definitely a repeatable problem." This was someone commenting on my thread about 3600x cards but he mentions the 3400x and not the 3600x.

Another post down the thread, we have this: "Got a pair of 3600x 256gb on my um4k. I've nothing to say about them, they just work fine. But I see no reason to buy them in case you have no dropped frames using 3400x."

Now I am confused. Perhaps the person posted the same information in more than one place as you are quoting a problem with 3400x cards while this thread mentions 3600x cards failing in dual recording:warning: using 2 cards with Ursa Mini 4kviewtopic.php?t=45896

I have ordered four 256GB Lexar 3400x cards. They will arrive probably end of this week or early next week. Anyone based in Los Angeles that has a URSA Mini 4.6K and would like to test them out before investing can PM me to meet-up. I am more than happy to lend them. You could post results for all to know. My URSA Mini is still on backorder status, so it will be a while before I will be able to test my cards personally.

rick.lang wrote:Now I am confused. Perhaps the person posted the same information in more than one place as you are quoting a problem with 3400x cards while this thread mentions 3600x cards failing in dual recording:warning: using 2 cards with Ursa Mini 4kviewtopic.php?t=45896

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Hmmm ... I'm befuddled. The BMD post and the one under my post on BMCuser is worded similarly. Well ... Lexar has approved the 3600x card for the Ursa 4.6k. So, if they don't work, I suppose I can take it up with them. I bought these cards, months ago after the 3400x cards were discontinued. I am too cautious to order 3400x cards from China. I hope the BMD has been working with Lexar.

paulvanmondfrans wrote:I really hope the Transcend CFX650 will work on the 4.6K. They are a bargain here in the Netherlands. Anyone with a mini46 tested these yet?

Had a chance to test the 4.6k with the two cfast cards I have. One CFX650 and a Lexar 3400x. The transcend works flawlessly in 60fps uncompressed raw. The lexar started dropping frames left and right after several seconds in this mode. Not sure if the lexar I got from ebay is defective or if it simply can't keep up.

paulvanmondfrans wrote:I really hope the Transcend CFX650 will work on the 4.6K. They are a bargain here in the Netherlands. Anyone with a mini46 tested these yet?

Had a chance to test the 4.6k with the two cfast cards I have. One CFX650 and a Lexar 3400x. The transcend works flawlessly in 60fps uncompressed raw. The lexar started dropping frames left and right after several seconds in this mode. Not sure if the lexar I got from ebay is defective or if it simply can't keep up.

If the Transcend CFX650 works as well as Jack says, is there any reason not to get it over the Lexar 3600X?Are they known to be less reliable? They certainly are cheaper!

RAW, 4.6k, 60fps = dropped frames. Kept recording on to the second card, and the first card was not corrupted.

RAW 3:1, 4.6k, 60fps = no dropped frames. Kept recording on to the second card, and the first card was not corrupted.

Single card:

RAW, 4.6k, 60fps = dropped frames

RAW 3:1, 4.6k, 60fps = no dropped frames.

3840x2160 ProRes444XQ does not provide option for 40fps, only 30fps and lower

2K raw (windowed): I set the sensor rate to 120fps and there were no dropped frames.

I hope that helps.

Since Matt White posted his test of the Lexar 3600X dropping frames in the 60fps uncompressed RAW mode (originally posted in the list of approved CFast card thread) And Jack Liu reports flawless performance with the Transcend CFX650 in that same mode, It seems like a no brainer to go for the Transcend CFX650 cards, especially when you can get them for $518.22 on Amazon. I was initially drawn to the Lexar simply because of brand recognition and a better perceived reliability factor (which may or may not be true). But if the Transcend performs better, that goes a long way toward actually being the better choice for the 4.6k regardless of brand name. I have one arriving soon and I'll check it out myself and report back here.

Numbers are fine, but isn't it the observed performance that counts? If we go by the numbers, the Lexar 3600X should perform better than the Transcend, but it doesn't, at least reported so far by Jack Liu. He says that a single Transcend card performed flawlessly at 60fps 4.6k uncompressed RAW. I have one coming soon, so I hope I can duplicate that finding.

I just tested 2 lexar 3400x (discontinued, $75 dollar eBay cards from China) in dual card mode and they worked just fine at 60fps uncompressed raw. But it did fill up both cards with only 7 minutes of record time.

jasonparker wrote:I just tested 2 lexar 3400x (discontinued, $75 dollar eBay cards from China) in dual card mode and they worked just fine at 60fps uncompressed raw. But it did fill up both cards with only 7 minutes of record time.

I got this information from my vendor, who said that at this time there is no CFAST card fast enough to record the full capacity of the camera (4.6k RAW 60fps), so the only way to use that setting is with an external recorder. via SDI.

Personally, I have no need for uncompressed raw right now, so I am not concerned.

I think he's talking about the 128Gb Lexar 3400x - they were going for $75 for a while with "Make Offer" but now they've gone back up, I can't get anyone to agree to less than $118 now. At that point I'd rather spend a couple pennies more per Gb and get the 256Gb 3400x at $250.

paulvanmondfrans wrote:I really hope the Transcend CFX650 will work on the 4.6K. They are a bargain here in the Netherlands. Anyone with a mini46 tested these yet?

Had a chance to test the 4.6k with the two cfast cards I have. One CFX650 and a Lexar 3400x. The transcend works flawlessly in 60fps uncompressed raw. The lexar started dropping frames left and right after several seconds in this mode. Not sure if the lexar I got from ebay is defective or if it simply can't keep up.

Jack Liu, Thanks for your report. How long were you able to record 4.6k 60fps uncompressed RAW using a single Transcend CFX650 card?

jasonparker wrote:I just tested 2 lexar 3400x (discontinued, $75 dollar eBay cards from China) in dual card mode and they worked just fine at 60fps uncompressed raw. But it did fill up both cards with only 7 minutes of record time.

Matt White wrote:I got this information from my vendor, who said that at this time there is no CFAST card fast enough to record the full capacity of the camera (4.6k RAW 60fps), so the only way to use that setting is with an external recorder. via SDI.

Personally, I have no need for uncompressed raw right now, so I am not concerned.

Matt, true 60 fps uncompressed raw exceeds the recording capability of an existing CFast 2 card in the URSA/Mini. But remember two things:

First, 'uncompressed' is actually lossless compressed raw much like you can zip a data file and then unzip it without any loss of data. That lossless compression fa or varies with your scene but is likely somewhere in the range of 1.2x to 1.5x for video. Generally I assume a factor of 1.3, but to play it safe, let's assume it's 1.25x for our busy video.

Second, for high frame rates, the CinemaDNG raw files are supposed to use the camera's dual record option, so all odd DNG frames are on one card and the even DNG frames on the other card.

You need to use both of those things to allow you to record raw 60 fps open gate on the 4.6K sensor. The camera always records uncompressed raw as lossless compressed raw, but you need to select the dual record option with two cards in the slots.

So you need two cards each of which must record with a sustained data rate of 430,269,696 bytes per second. The Lexar 3600x cards are rated at 445 MB/s. So they should work depending upon the amount of lossless compression.

The Transcend 3400x CFX650 cards are rated at 370 MB/s. They should fail except on simpler scenes that permit higher values of lossless compression.

If I'm correct in that assumption:the Transcend's 370 MB/s is actually 387,973,120 bytes per second. Subtracting 288,000 bytes per second for audio, leaves 387,685,120 for video. With a perfectly reasonable lossless compression factor of 1.4x, this can be done. But in a very busy scene the Transcend may have dropped frames.

I am now consistently getting good results using dual card mode, recording 4.6k RAW 60fps. I have not been able to repeat the dropped frames I initially observed. I do not know why. Nevertheless, it appears that the 3600x cards DO record uncompressed RAW in dual card mode.

If I'm correct in that assumption:the Transcend's 370 MB/s is actually 387,973,120 bytes per second. Subtracting 288,000 bytes per second for audio, leaves 387,685,120 for video. With a perfectly reasonable lossless compression factor of 1.4x, this can be done. But in a very busy scene the Transcend may have dropped frames.

Hi Rick Lang, Thanks for your through breakdown. I have received one Transcend CFX650 card, but have not opened the package yet, so it's still returnable. I went for it based solely on Jack Liu's report of flawless performance with no dropped in 4.6k Uncompressed RAW at 60fps. Is it possible he got these results with a single card? Maybe he was recording a blank wall? I won't be too upset if I don't get the same results he did on a single card, but, do you think two Transcend CFX650s will work in dual card mode with 4.6k Uncompressed RAW at 60fps? Thanks,Benton

If I'm correct in that assumption:the Transcend's 370 MB/s is actually 387,973,120 bytes per second. Subtracting 288,000 bytes per second for audio, leaves 387,685,120 for video. With a perfectly reasonable lossless compression factor of 1.4x, this can be done. But in a very busy scene the Transcend may have dropped frames.

Hi Rick Lang, Thanks for your through breakdown. I have received one Transcend CFX650 card, but have not opened the package yet, so it's still returnable. I went for it based solely on Jack Liu's report of flawless performance with no dropped in 4.6k Uncompressed RAW at 60fps. Is it possible he got these results with a single card? Maybe he was recording a blank wall? I won't be too upset if I don't get the same results he did on a single card, but, do you think two Transcend CFX650s will work in dual card mode with 4.6k Uncompressed RAW at 60fps? Thanks,Benton

Hard to comment on Jack's post, but I am skeptical that the scene involved significant motion and complex detail. Two Transcend's may well work when the raw lossless compression factor is approaching 1.4x and it may also be that Transcend has been conservative in their performance numbers which is a good thing.

I don't think it would hurt to have a pair of Transcend's cards and a pair of Lexar's cards. Then with testing you can learn which is better. I think it was CaptainHook who has posted that the Transcend cards actually did better recording ProRes and the Lexar cards did better recording raw. So it may make sense to have both brands. I'd follow the Captain's guidance but best to test yourself.

If I'm correct in that assumption:the Transcend's 370 MB/s is actually 387,973,120 bytes per second. Subtracting 288,000 bytes per second for audio, leaves 387,685,120 for video. With a perfectly reasonable lossless compression factor of 1.4x, this can be done. But in a very busy scene the Transcend may have dropped frames.

Hi Rick Lang, Thanks for your through breakdown. I have received one Transcend CFX650 card, but have not opened the package yet, so it's still returnable. I went for it based solely on Jack Liu's report of flawless performance with no dropped in 4.6k Uncompressed RAW at 60fps. Is it possible he got these results with a single card? Maybe he was recording a blank wall? I won't be too upset if I don't get the same results he did on a single card, but, do you think two Transcend CFX650s will work in dual card mode with 4.6k Uncompressed RAW at 60fps? Thanks,Benton

Hard to comment on Jack's post, but I am skeptical that the scene involved significant motion and complex detail. Two Transcend's may well work when the raw lossless compression factor is approaching 1.4x and it may also be that Transcend has been conservative in their performance numbers which is a good thing.

I don't think it would hurt to have a pair of Transcend's cards and a pair of Lexar's cards. Then with testing you can learn which is better. I think it was CaptainHook who has posted that the Transcend cards actually did better recording ProRes and the Lexar cards did better recording raw. So it may make sense to have both brands. I'd follow the Captain's guidance but best to test yourself.

Thanks Rick, I was thinking the same thing that having a pair of each type of card wouldn't hurt. Except in the wallet of course! But such is the price for this type of performance! I have a project coming up where I would feel less than prepared with less than four 256gb cards anyway. So I guess it's a bullet to be bitten!

Probably not. I'll stick with either RAW or 3:1 RAW throughout. The majority will be standard 24fps. Only occasionally 60fps. which is where I will use the dual Lexar cards. Do you think the Transcend's will work ok in standard RAW or 3:1?

rick.lang wrote:I don't think it would hurt to have a pair of Transcend's cards and a pair of Lexar's cards. Then with testing you can learn which is better.

You're right Rick and that is solid advice, but damn that's a shame it's what we're all going to have to do. The switch to cFast supposed to save us from the dropped frame uncertainties of SSD drives that we had to deal with on the BMCC and the production camera, right? Honestly, BMD really should be providing us with unequivocal answers about which cards are best for the 4.6K. They should have done enough testing before the camera shipped. They certainly had plenty of time for it during the long months of beta testing.

Benton, for uncompressed raw (actually lossless compressed) at 60 fps they might handle simpler scenes but I think they would not be trustworthy. On the other hand, they should be good for raw 3:1 60 fps which requires about a third of the data rate of truly uncompressed raw. You could experiment with a single card but more complex scenes might be problematic and dual recording would be a breeze at 60 fps.

Everybody should be shooting be 4:1 Raw there cant really be any discernible difference to the eye. And the audience is definitely not going to know if you shot Raw or 4:1 Raw. If it doesn't need a quick Pro Res turn around 4:1 Raw all day.

You shot on the 3400 lexar? About to take the plunge and order the UM46. Saw the threads about 70 bucks for 128 GB lexar 3400x on ebay. Want to order 2 to start with. I also have the shogun, and i had planned to record everything onto it (except 2160p60). So I want to know if two lexar 3400's and the shogun recording most of my stuff will work until CFast card prices come down for us mere mortal.

I shoot music vids, docus and commercials. So mostly 25fps (Pal world) and some 60 for the heck of it. 120 is too slow except for Docu work.

jasonparker wrote:I just tested 2 lexar 3400x (discontinued, $75 dollar eBay cards from China) in dual card mode and they worked just fine at 60fps uncompressed raw. But it did fill up both cards with only 7 minutes of record time.

jasonparker wrote:I just tested 2 lexar 3400x (discontinued, $75 dollar eBay cards from China) in dual card mode and they worked just fine at 60fps uncompressed raw. But it did fill up both cards with only 7 minutes of record time.

Shot yesterday on 2 Lexar 3600x 256gb cards. No problems with spanning cards in ProRes and no problems with any clips. Shot ProRes HQ and some shots in 3:1 RAW. Still need to test them in Uncompressed RAW.

If there is a different list for the 4.6 models, I would expect it to appear around the time of NAB or shortly there after as we are in the final stages or preparation for the trade show.

Regards,

Tony RiveraBlackmagic Design

Ticket HistoryDave Perry (Client) Posted On: 07 April 2016 09:27 AM

Thanks Tony. I mainly wanted to confirm that the ones listed for the 4K Ursas worked for the 4.6 as well. There doesn’t seem to be a list for the 4.6k sensor.

Thanks.

dp

Tony Rivera (Staff) Posted On: 07 April 2016 09:06 AM

Hello Dave,

We'd suggest at this time sticking with the ones on our approved CFast list from the support page (https://www.blackmagicdesign.com/support/faq/59008). As far as other cards being added, I do know that we are working on approval of more but I do not have a time frame for when that list will be updated currently.

For me I've used the x3400 extensively. Very very extensively and through all the settings. Not one hiccup except 60p uncompressed. 60p 3:1 works. I think just that there's so many hesitations adds toThe current confusion. The caveat is that this could change of course but right now they are working brilliantly.